html, body {
  width:100%;
  height: 100%;
  overflow:hidden;
  background:#000;
}

body { margin: 0; }

div {
  position: absolute;
  box-sizing:border-box;
}

.container {
  width: 300px;
  height: 300px;
  perspective: 1500px;
  left:50%;
  top:50%;
  transform:translate(-50%,-50%);
}

#cube {
  height: 100%;
  width: 100%;
  transform-style: preserve-3d;
  position: relative;
}

.face {
  height: 100%;
  width: 100%;
  user-select:none;
  top: 0;
  left: 0;
  backface-visibility: hidden;
}